This file is indexed.

/usr/lib/python2.7/dist-packages/billiard/queues.py is in python-billiard 3.3.0.15-1ubuntu1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
#
# Module implementing queues
#
# multiprocessing/queues.py
#
# Copyright (c) 2006-2008, R Oudkerk
# Licensed to PSF under a Contributor Agreement.
#
from __future__ import absolute_import

__all__ = ['Queue', 'SimpleQueue', 'JoinableQueue']

import sys
import os
import threading
import collections
import weakref
import errno

from . import Pipe
from ._ext import _billiard
from .compat import get_errno
from .five import monotonic
from .synchronize import Lock, BoundedSemaphore, Semaphore, Condition
from .util import debug, error, info, Finalize, register_after_fork
from .five import Empty, Full
from .forking import assert_spawning


class Queue(object):
    '''
    Queue type using a pipe, buffer and thread
    '''
    def __init__(self, maxsize=0):
        if maxsize <= 0:
            maxsize = _billiard.SemLock.SEM_VALUE_MAX
        self._maxsize = maxsize
        self._reader, self._writer = Pipe(duplex=False)
        self._rlock = Lock()
        self._opid = os.getpid()
        if sys.platform == 'win32':
            self._wlock = None
        else:
            self._wlock = Lock()
        self._sem = BoundedSemaphore(maxsize)
        # For use by concurrent.futures
        self._ignore_epipe = False

        self._after_fork()

        if sys.platform != 'win32':
            register_after_fork(self, Queue._after_fork)

    def __getstate__(self):
        assert_spawning(self)
        return (self._ignore_epipe, self._maxsize, self._reader, self._writer,
                self._rlock, self._wlock, self._sem, self._opid)

    def __setstate__(self, state):
        (self._ignore_epipe, self._maxsize, self._reader, self._writer,
         self._rlock, self._wlock, self._sem, self._opid) = state
        self._after_fork()

    def _after_fork(self):
        debug('Queue._after_fork()')
        self._notempty = threading.Condition(threading.Lock())
        self._buffer = collections.deque()
        self._thread = None
        self._jointhread = None
        self._joincancelled = False
        self._closed = False
        self._close = None
        self._send = self._writer.send
        self._recv = self._reader.recv
        self._poll = self._reader.poll

    def put(self, obj, block=True, timeout=None):
        assert not self._closed
        if not self._sem.acquire(block, timeout):
            raise Full

        with self._notempty:
            if self._thread is None:
                self._start_thread()
            self._buffer.append(obj)
            self._notempty.notify()

    def get(self, block=True, timeout=None):
        if block and timeout is None:
            with self._rlock:
                res = self._recv()
                self._sem.release()
                return res

        else:
            if block:
                deadline = monotonic() + timeout
            if not self._rlock.acquire(block, timeout):
                raise Empty
            try:
                if block:
                    timeout = deadline - monotonic()
                    if timeout < 0 or not self._poll(timeout):
                        raise Empty
                elif not self._poll():
                    raise Empty
                res = self._recv()
                self._sem.release()
                return res
            finally:
                self._rlock.release()

    def qsize(self):
        # Raises NotImplementedError on Mac OSX because
        # of broken sem_getvalue()
        return self._maxsize - self._sem._semlock._get_value()

    def empty(self):
        return not self._poll()

    def full(self):
        return self._sem._semlock._is_zero()

    def get_nowait(self):
        return self.get(False)

    def put_nowait(self, obj):
        return self.put(obj, False)

    def close(self):
        self._closed = True
        self._reader.close()
        if self._close:
            self._close()

    def join_thread(self):
        debug('Queue.join_thread()')
        assert self._closed
        if self._jointhread:
            self._jointhread()

    def cancel_join_thread(self):
        debug('Queue.cancel_join_thread()')
        self._joincancelled = True
        try:
            self._jointhread.cancel()
        except AttributeError:
            pass

    def _start_thread(self):
        debug('Queue._start_thread()')

        # Start thread which transfers data from buffer to pipe
        self._buffer.clear()
        self._thread = threading.Thread(
            target=Queue._feed,
            args=(self._buffer, self._notempty, self._send,
                  self._wlock, self._writer.close, self._ignore_epipe),
            name='QueueFeederThread'
        )
        self._thread.daemon = True

        debug('doing self._thread.start()')
        self._thread.start()
        debug('... done self._thread.start()')

        # On process exit we will wait for data to be flushed to pipe.
        #
        # However, if this process created the queue then all
        # processes which use the queue will be descendants of this
        # process.  Therefore waiting for the queue to be flushed
        # is pointless once all the child processes have been joined.
        created_by_this_process = (self._opid == os.getpid())
        if not self._joincancelled and not created_by_this_process:
            self._jointhread = Finalize(
                self._thread, Queue._finalize_join,
                [weakref.ref(self._thread)],
                exitpriority=-5
            )

        # Send sentinel to the thread queue object when garbage collected
        self._close = Finalize(
            self, Queue._finalize_close,
            [self._buffer, self._notempty],
            exitpriority=10
        )

    @staticmethod
    def _finalize_join(twr):
        debug('joining queue thread')
        thread = twr()
        if thread is not None:
            thread.join()
            debug('... queue thread joined')
        else:
            debug('... queue thread already dead')

    @staticmethod
    def _finalize_close(buffer, notempty):
        debug('telling queue thread to quit')
        with notempty:
            buffer.append(_sentinel)
            notempty.notify()

    @staticmethod
    def _feed(buffer, notempty, send, writelock, close, ignore_epipe):
        debug('starting thread to feed data to pipe')
        from .util import is_exiting

        ncond = notempty
        nwait = notempty.wait
        bpopleft = buffer.popleft
        sentinel = _sentinel
        if sys.platform != 'win32':
            wlock = writelock
        else:
            wlock = None

        try:
            while 1:
                with ncond:
                    if not buffer:
                        nwait()
                try:
                    while 1:
                        obj = bpopleft()
                        if obj is sentinel:
                            debug('feeder thread got sentinel -- exiting')
                            close()
                            return

                        if wlock is None:
                            send(obj)
                        else:
                            with wlock:
                                send(obj)
                except IndexError:
                    pass
        except Exception as exc:
            if ignore_epipe and get_errno(exc) == errno.EPIPE:
                return
            # Since this runs in a daemon thread the resources it uses
            # may be become unusable while the process is cleaning up.
            # We ignore errors which happen after the process has
            # started to cleanup.
            try:
                if is_exiting():
                    info('error in queue thread: %r', exc, exc_info=True)
                else:
                    if not error('error in queue thread: %r', exc,
                                 exc_info=True):
                        import traceback
                        traceback.print_exc()
            except Exception:
                pass

_sentinel = object()


class JoinableQueue(Queue):
    '''
    A queue type which also supports join() and task_done() methods

    Note that if you do not call task_done() for each finished task then
    eventually the counter's semaphore may overflow causing Bad Things
    to happen.
    '''

    def __init__(self, maxsize=0):
        Queue.__init__(self, maxsize)
        self._unfinished_tasks = Semaphore(0)
        self._cond = Condition()

    def __getstate__(self):
        return Queue.__getstate__(self) + (self._cond, self._unfinished_tasks)

    def __setstate__(self, state):
        Queue.__setstate__(self, state[:-2])
        self._cond, self._unfinished_tasks = state[-2:]

    def put(self, obj, block=True, timeout=None):
        assert not self._closed
        if not self._sem.acquire(block, timeout):
            raise Full

        with self._notempty:
            with self._cond:
                if self._thread is None:
                    self._start_thread()
                self._buffer.append(obj)
                self._unfinished_tasks.release()
                self._notempty.notify()

    def task_done(self):
        with self._cond:
            if not self._unfinished_tasks.acquire(False):
                raise ValueError('task_done() called too many times')
            if self._unfinished_tasks._semlock._is_zero():
                self._cond.notify_all()

    def join(self):
        with self._cond:
            if not self._unfinished_tasks._semlock._is_zero():
                self._cond.wait()


class _SimpleQueue(object):
    '''
    Simplified Queue type -- really just a locked pipe
    '''

    def __init__(self, rnonblock=False, wnonblock=False):
        self._reader, self._writer = Pipe(
            duplex=False, rnonblock=rnonblock, wnonblock=wnonblock,
        )
        self._poll = self._reader.poll
        self._rlock = self._wlock = None
        self._make_methods()

    def empty(self):
        return not self._poll()

    def __getstate__(self):
        assert_spawning(self)
        return (self._reader, self._writer, self._rlock, self._wlock)

    def __setstate__(self, state):
        (self._reader, self._writer, self._rlock, self._wlock) = state
        self._make_methods()

    def _make_methods(self):
        recv = self._reader.recv
        try:
            recv_payload = self._reader.recv_payload
        except AttributeError:
            recv_payload = self._reader.recv_bytes
        rlock = self._rlock

        if rlock is not None:
            def get():
                with rlock:
                    return recv()
            self.get = get

            def get_payload():
                with rlock:
                    return recv_payload()
            self.get_payload = get_payload
        else:
            self.get = recv
            self.get_payload = recv_payload

        if self._wlock is None:
            # writes to a message oriented win32 pipe are atomic
            self.put = self._writer.send
        else:
            send = self._writer.send
            wlock = self._wlock

            def put(obj):
                with wlock:
                    return send(obj)
            self.put = put


class SimpleQueue(_SimpleQueue):

    def __init__(self):
        self._reader, self._writer = Pipe(duplex=False)
        self._rlock = Lock()
        self._wlock = Lock() if sys.platform != 'win32' else None
        self._make_methods()